Hi,
You can share the dashboard with guest users whose addresses are outside your organization, recipients will need either a Power Bi Pro or Premium Per user license, unless you're using a premium capacity SKU.
Use a security group (not a distribution group), to share with a group that includes people with external email addresses. People with external emails in a distribution group can't see the content you share, unless they're Azure AD B2B guest users. More info on sharing outside of your org can be found here.
Hope this helps.
KR,
Peter